JPH0328386A - Method for pickling metal - Google Patents
Method for pickling metalInfo
- Publication number
- JPH0328386A JPH0328386A JP16173289A JP16173289A JPH0328386A JP H0328386 A JPH0328386 A JP H0328386A JP 16173289 A JP16173289 A JP 16173289A JP 16173289 A JP16173289 A JP 16173289A JP H0328386 A JPH0328386 A JP H0328386A
- Authority
- JP
- Japan
- Prior art keywords
- pickling
- acid
- concentration
- concn
- solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000005554 pickling Methods 0.000 title claims abstract description 135
- 239000002184 metal Substances 0.000 title claims abstract description 20
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title claims description 30
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 69
- 239000002253 acid Substances 0.000 claims abstract description 64
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 39
- 229910052742 iron Inorganic materials 0.000 claims abstract description 37
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 31
- 239000003014 ion exchange membrane Substances 0.000 claims abstract description 10
- -1 iron ions Chemical class 0.000 claims description 29
- 150000002739 metals Chemical class 0.000 claims description 6
- 238000011084 recovery Methods 0.000 abstract description 9
- 239000000203 mixture Substances 0.000 abstract description 7
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 4
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 abstract description 4
- 150000007513 acids Chemical class 0.000 abstract description 4
- 230000003247 decreasing effect Effects 0.000 abstract description 4
- 239000002699 waste material Substances 0.000 abstract description 4
- 229910001447 ferric ion Inorganic materials 0.000 abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 3
- 150000002500 ions Chemical class 0.000 abstract description 2
- 229910001448 ferrous ion Inorganic materials 0.000 abstract 2
- XWROUVVQGRRRMF-UHFFFAOYSA-N F.O[N+]([O-])=O Chemical compound F.O[N+]([O-])=O XWROUVVQGRRRMF-UHFFFAOYSA-N 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 57
- 229910001220 stainless steel Inorganic materials 0.000 description 11
- 239000010935 stainless steel Substances 0.000 description 10
- 238000007796 conventional method Methods 0.000 description 8
- 238000001704 evaporation Methods 0.000 description 8
- 230000008020 evaporation Effects 0.000 description 8
- 230000007423 decrease Effects 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- 238000012545 processing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 229910000851 Alloy steel Inorganic materials 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- QPJSUIGXIBEQAC-UHFFFAOYSA-N n-(2,4-dichloro-5-propan-2-yloxyphenyl)acetamide Chemical compound CC(C)OC1=CC(NC(C)=O)=C(Cl)C=C1Cl QPJSUIGXIBEQAC-UHFFFAOYSA-N 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 239000002436 steel type Substances 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000000502 dialysis Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000011550 stock solution Substances 0.000 description 2
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 239000003788 bath preparation Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 229910001105 martensitic stainless steel Inorganic materials 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/086—Iron or steel solutions containing HF
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/36—Regeneration of waste pickling liquors
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
Description
（産業上の利用分野）
この発明は、ステンレス鋼，＃熱鋼などの高合金鋼や、
ニッケル基合金，チタン基合金などの高合金等の弗酸（
Ｈ Ｆ）系の酸を用いて酸洗処理が行われる金属に対し
て酸洗処理を行うのに利用される金属の酸洗処理方法に
関するものである．
（従来の技術）
従来、例えばステンレス鋼などの高合金鋼鋼材を熱間加
工した場合や熱処理した場合などにおいては、その表面
に酸化スケールが生威する．
そこで、このような酸化スケールを除去するに際１，テ
は、硝ｆｍ （ＨＮＯ３ ） や弗ｍ （ＩＦ） と（
１）梶合液である弗硝酸液を酸洗液として用いている．
このステンレス鋼などの高合金鋼鋼材の酸洗処理におい
て用いられる弗硝酸液は、酸洗処理を行うにしたがって
、その酸濃度が次第に低下する．そして、通常の場合に
この酸洗液はそのＭＷ度が低くなるまで使用され、例え
ば酸濃度が高いうちはＮｉ系のステンレス鋼の酸洗処理
を例えばＮｉ含有量の多い順に複数種類にわたって行い
、酸濃度がある程度まで低下したときにはＣｒ系のステ
ンレス鋼の酸洗処理を例えばまずフエライト系ステンレ
ス鋼次いでマルテンサイト系ステンレス鋼というように
複数種類にわたって行うようにしている．
したがって，酸洗液中には酸洗処理鋼材から各種の金属
が溶出し、その金属イオン濃度が増加して酸洗液の酸洗
力は弱くなる．
そして、酸洗力を最も必要としない脱スケールのしゃす
い鋼種に対しても酸洗力を失った時点で新たな酸洗液を
追加することにより酸洗槽内の酸洗液を再生するいわゆ
る建浴が行われるが、一般にこのような処理によっては
酸洗液の酸濃度の任意の調節は困難である．
他方、このような酸洗力が低下した酸洗液に新たな酸を
単純に追加して酸洗液を再生する方法のほかに、酸洗槽
内の酸洗浴を構虞する酸洗液を酸洗槽外に導き、イオン
交換膜により硝酸および弗酸を回収し、回収した酸に必
要に応じて新酸を補充して酸洗液の弗硝酸濃度を一定に
管理する定濃度酸洗処理方法の開発もあった．
（発明が解決しようとする課題）
このような酸洗液の弗硝酸濃度を一定に管理する方法で
は、高合金鋼や高合金の酸洗処理を行うに際して定濃度
操業を実施することが可能であるので、従来のように酸
洗処理の初期にはＮｉ系ステンレス鋼の酸洗処理を例え
ば複数種類にわたって行い、酸洗力がある程度低下した
ときにはＣｒ系ステンレス鋼の酸洗処理を例えば複数種
類にわたって行うというような酸洗力の低下に応じた鋼
種を選定する酸洗処理を行う必要がなくなり、例えば高
濃度の酸洗液に一定に雑持することによりＮｉ系ステン
レス鋼の酸洗処理を連続して行うようにしたり、また、
中濃度の酸洗液に一定に維持することによりＣｒ系ステ
ンレス鋼の酸洗処理を連続して行うようにしたり、さら
には、低濃度の酸洗液に一定に雑持することにより構造
用鋼の酸洗処理を連続して行うようにしたりすることが
可能であって、従来のように酸洗力の低下に応じて鋼種
を選定するという制約がなくなるという利点が得られる
が，このような定濃度酸洗処理においてもより一層の優
れた酸洗処理能力が錐持されるようにすることが望まれ
ていると共に、酸消費量のより一層の減少による酸コス
トの低下が望まれるという課題があった．
（発明の目的）
この発明は，このような従来の課題に着目してなされた
もので、酸洗液の濃度を一定にして行うステンレス鋼や
耐熱鋼などの高合金鋼や鉄を含む高合金等の金属に対す
る定濃度酸洗処理方法において、酸濃度を高めることな
く酸洗液の酸洗処理能力を大きなものに維持することが
でき，酸濃度の低下により酸コストのより一層の低減を
はかることができるようにすることを目的としている．(Industrial Application Field) This invention is applicable to high alloy steels such as stainless steel and #thermal steel,
Hydrofluoric acid (
This invention relates to a method for pickling metals, which is used for pickling metals using HF)-based acids. (Prior Art) Conventionally, when high-alloy steel materials such as stainless steel are hot-worked or heat-treated, oxide scale grows on their surfaces. Therefore, when removing such oxidized scale, the first step is to use nitrate fm (HNO3), fm (IF) and (
1) Fluoronitric acid solution, which is a slag mixture, is used as the pickling solution. The acid concentration of the fluoronitric acid solution used in the pickling treatment of high-alloy steel materials such as stainless steel gradually decreases as the pickling treatment is carried out. In normal cases, this pickling solution is used until its MW degree becomes low, and for example, while the acid concentration is high, pickling treatment of Ni-based stainless steel is performed on multiple types of stainless steel in descending order of Ni content. When the acid concentration has decreased to a certain level, multiple types of Cr stainless steel are pickled, for example, first ferritic stainless steel, then martensitic stainless steel. Therefore, various metals are eluted from the pickled steel into the pickling solution, and the metal ion concentration increases, weakening the pickling power of the pickling solution. Even for descaling tenacious steel types that do not require pickling power the most, we regenerate the pickling solution in the pickling tank by adding new pickling solution when it loses its pickling power. Although bath preparation is performed, it is generally difficult to arbitrarily adjust the acid concentration of the pickling solution through such processing. On the other hand, in addition to the method of regenerating the pickling solution by simply adding new acid to the pickling solution whose pickling power has decreased, it is also possible to regenerate the pickling solution that may constitute the pickling bath in the pickling tank. A constant concentration pickling process in which nitric acid and hydrofluoric acid are guided out of the pickling tank and recovered using an ion exchange membrane, and the recovered acid is replenished with new acid as needed to maintain a constant concentration of fluorinic acid in the pickling solution. There was also the development of a method. (Problem to be Solved by the Invention) With this method of controlling the fluoronitric acid concentration of the pickling solution at a constant level, it is possible to carry out constant concentration operation when pickling high alloy steel or high alloys. Therefore, as in the past, Ni-based stainless steel is pickled in multiple types at the beginning of the pickling process, and when the pickling power has decreased to a certain extent, Cr-based stainless steel is pickled in multiple types, for example. It is no longer necessary to carry out pickling treatment, which involves selecting steel types according to the drop in pickling power. or,
By maintaining a constant medium concentration pickling solution, pickling treatment of Cr-based stainless steel can be carried out continuously, and furthermore, by maintaining a constant pickling solution in a low concentration pickling solution, structural steel can be pickled. It is possible to carry out the pickling treatment continuously, which has the advantage of eliminating the conventional restriction of selecting the steel type according to the decrease in pickling power. The problem is that it is desired to maintain even better pickling processing ability even in constant concentration pickling processing, and it is also desirable to reduce acid cost by further reducing acid consumption. was there. (Purpose of the Invention) This invention has been made by focusing on such conventional problems. In the fixed concentration pickling treatment method for metals such as, the pickling ability of the pickling solution can be maintained at a high level without increasing the acid concentration, and the acid cost can be further reduced by lowering the acid concentration. The purpose is to make it possible.
（課題を解決するための手段）
この発明に係わる金属の酸洗処理方法は、酸洗槽内の酸
洗液を酸洗槽外に導き、イオン交換膜により硝酸および
弗酸を回収し、回収した酸に必要に応じて新酸を補充し
て酸洗液の弗硝酸濃度を一定に管理する金属の酸洗処理
方法において、酸洗液中のトータル鉄濃度を５０ｇ／！
Ｌ以下とし且つ２価の鉄イオン（ ｐ ｅ ２ ＋ ）
と３価の鉄イオン（ ｐ ｅ Ｗ ＋ ）の濃度比（Ｆ
ｅ２ ＋／ｐ’ ｅ３ ＋ ）を０．２５〜２．０の
範囲に制御する構成としたことを特徴としており、一実
施態様においては酸洗浴の硝酸濃度を０．３５〜０．６
０Ｎ、弗酸濃度を０．３０〜０．５０Ｎの範囲に制御す
るようにしたことを特徴としている．
この発明に係わる金属の酸洗処理方法においては、酸洗
槽内の酸洗浴を構戊する酸洗液を酸洗槽外に導き、イオ
ン交換膜により硝酸および弗酸を回収し、回収した酸に
必要に応じて新酸を補充して酸洗液の弗硝酸濃度を一定
に管理する定濃度酸洗処理を対象としているが、第１図
はこの定濃度酸洗処理の実施態様を示すものである．す
なわち、第１図に示すように，酸洗液として弗酸と硝酸
との混合液である弗硝酸液１を収容した酸洗槽２と、イ
オン交換膜による拡散透析法を利用した酸回収装置３と
を配管４で接続し，酸回収装置３の回収液出口に接続し
た配管５を酸洗槽２の上部側に配設した構威をなすもの
である．
そこで、例えばステンレス鋼の酸洗処理を行う間におい
て、この酸洗処理によって濃度が低下した弗硝酸液１を
配管４を通して酸回収装置３内に原液として送り込むと
共に，配管６を通して水を送り込む．この酸回収装！ｌ
３内では、前記原液と水とが供給されつつイオン交換膜
を用いた拡散透析法によって酸回収処理がなされ、弗酸
および硝酸を回収した回収液と排弗硝酸液とが送り出さ
れ、回収液は配管５を通して酸洗槽２内に送られ、排弗
硝酸液は配管７を通して排出され、この排弗硝酸液は中
和処理して廃棄されたり他の用途に適用されたりし、酸
洗槽１においては必要な新酸が配管８より供給されて、
定濃度酸洗処理が行われる．
この発明に係わる金属の酸洗処理方法においては、上記
したように、酸洗液の弗硝酸濃度を一定に管理する定濃
度操業において、酸洗液中のトータル鉄濃度を５ ０
ｇ ／ ！Ｌ以下とし且つ２価の鉄イオン（Ｆｅ”）と
３価の鉄イオン（Ｆｅ”）の濃度比（ ｝’ ｅ ２
＋／ Ｆｅ ３ ＋ ）を０．２５〜２．０の範囲に制
御するようにしているが、このように限定することとし
た理由について述べる．
第２図は、弗酸（Ｈ Ｆ）と硝酸（ＨＮＯ３）との混合
液である弗硝酸液を酸洗液として用いた酸洗処理におい
て、酸洗液中の２価の鉄イオン（ Ｆ ｅ ２ ＋ ）
と３価の鉄イオ７ （Ｆｅ’ ”） （１）Ｄ度比（Ｆ
ｅ２”／Ｆｅ’ ＋）と脱スケール力との関係を調べた
結果を示すもので，２価の鉄イオン（ ｐ ｅ ２ ＋
）と３価の鉄イオン（Ｆｅ”）とのバランスが脱スケ
ールカに大きく影響することが明らかであった．
すなわち，第２図の縦軸において，脱スケール力３は完
全に脱スケールされる酸洗力を有することを示し、脱ス
ケールカ２は点状にスケール残を生ずる酸洗力を有する
ことを示し、脱スケール力１は線または面状にスケール
残を生ずる酸洗力を有することを示しているものであっ
て、弗硝酸を用いた酸洗液において、鉄イオン濃度比（
Ｆｅ”／Ｆｅ”）が１．０＊−ｔ’は３価の鉄イオン（
Ｆｅ’や）の方が多いことから脱スケールカは強いもの
となっていることが明らかであるが，２価の鉄イオン（
Ｆｅ２＋）が増えるに従ってつまり鉄イオン濃度比（Ｆ
ｅ２◆／ Ｆ ｅ ８◆）が１．０を超えると脱スケー
ルカの低下が認められる．
このように、２価の鉄イオン（ Ｆｅ ２ ＋ ）が増
えるに従って脱スケールカの低下が認められるが、実操
業においては鉄イオン濃度比（ ｐ’ ６ ２ ＋／
ＦｅＡ＋）が２．０程度であっても十分な脱スケールカ
を有しているので，酸洗浴中の鉄イオン濃度比（Ｆ ｅ
２ ＋ ／Ｆ ｅ３ ＋ ）を２．０以下とした．
また、酸洗槽内の酸洗液を酸洗槽外に導き、イオン交換
膜により硝酸および弗酸を回収し、回収した酸に必要に
応じて新酸を補充して酸洗浴の弗硝酸濃度を一定に管理
する定濃度操業を行うに際しては，酸洗液の鉄イオン濃
度比（Ｆｅ”／Ｆｅ３＋）を０．２５未満に制御するこ
とは操業維持の観点からいって現実には困難であるので
、鉄イオン濃度比（Ｆｅ”／Ｆｅ”）の下限は０．２５
とした．
このように，弗硝酸液を用いた酸洗処理を行うに際して
、脱スケールのためには弗酸（Ｈ Ｆ）および硝酸（Ｈ
ＮＯ３）を高濃度レベルにする必要はなく、むしろ鉄イ
オン濃度比（Ｆｅ”／Ｆｅ Ｗ ＋ ）を適正範囲に設
定することが重要であることが認められ，この発明に係
わる酸洗処理方法辷おいては鉄イオン濃度比（ Ｆｅ
２ ＋ ／Ｆｅ＋ｓ◆）が０．２５ 〜２．０（７）範
囲に制御することとしている．
一方、酸洗液中の鉄濃度が多すぎるときにも酸洗力の低
下をきたすこととなるので、酸洗液中のトータル鉄濃度
を５ ０ ｇ ／ ｆＬ以下に制御することとした．
第３図は酸洗浴温度および硝酸濃度による硝酸の蒸発へ
の影響を示すもので、斜線で示した従来の使用＠囲では
大部分が硝酸の蒸発領域にある．したがって、このよう
な硝酸濃度および酸洗浴温度の弗硝酸液を一定に調節し
ようとすれば、硝酸の蒸発量が多いことから次から次へ
と補給せねばならず、硝酸の使用量がかなり多いものと
なる．
一方、前述したように、脱スケールに際して鉄イオン濃
度比（ ｐ ｅ ２＋／ Ｆｅ Ａ ＋ ）を適正範囲
に制御すれば硝酸および弗酸を必ずしも高濃度のものに
する必要のないことが明らかとなったので、酸洗液中の
硝＃濃度はその蒸発開始ライン以下である０．３５〜０
．６０Ｎ程度と低めに制御することが望ましい．また、
高濃度操業による例えばＮｉ系ステンレス鋼の酸洗処理
や、中濃度操業による例えばＣｒ系ステンレス鋼の酸洗
処理や、低濃度操業による例えば構造用鋼の酸洗処理が
行えるように、前記硝酸（ＨＮＯ３）と共に弗酸（Ｈ
Ｆ）の濃度を定めるようにすることが望ましく，この弗
酸の濃度においても０．３０〜０．５０Ｎ程度と低めに
制御することが望ましい．
このような弗硝酸液を用いた酸洗処理による脱スケール
機構を考えると、ｆＪＩＪ４図に示すように、脱スケー
ル作用を発揮するのは弗酸（Ｈ Ｆ）および３価の鉄イ
オン（ ｐ’ ｅ ３ ＋ ）であって、硝酸（ＨＮＯ
ａ）は３価の鉄イオン（Ｆｅ”）がアタックして２価の
鉄イオン（Ｆｅ２＋）に変わったものを再度脱スケール
力のある３価の鉄イオン（ ｐ ｅ ３ ＋ ）に戻す
いわゆる触媒の作用をもつことがわかった．
したがって，前述したように、２価の鉄イオンＣＦ，２
＋）と３価の鉄イオン（ＦｅＡ中）とのバランスをうま
く保ってやれば，硝酸（ＨＮＯ３）の濃度を低いレベル
に抑えたとしても十分な脱スケール性が得られ、硝酸の
蒸発をも抑えることができることがわかった．
（発明の作用）
この発明に係わる金属の酸洗処理方法では、上述した構
戊としているので，弗硝酸液の濃度が低いときでも十分
に強い酸洗力が得られることとなり、酸濃度の低下によ
って酸の蒸発損失も小さなものになるという作用がもた
らされる．（実施例）
供試材として、第１表に示す組威のＳＵＳ３１０，ＳＵ
Ｓ ＸＭ７，ＳＵＳ ３０４を選択し、第２表に示
す酸洗液組或および温度にょる酸洗処理，すなわち従来
法においては１０ｔｏｎ処理後の高濃度および２００ｔ
ｏｎ処理後の中濃度での酸洗処理を行い、本発明におい
ては高濃度，中濃度，低濃度の三種の酸回収による定濃
度酸洗処理を行って、それらの際の脱スケール時間を調
べた．
この結果を第５図に示す．
第２表および第５図より明らかなように、本発明法と従
来法とにおける脱スケール力を比較してみると、本発明
法による酸回収高濃度酸洗液の脱スケール力は、従来法
に比べて酸濃度がかなり低いにもかかわらず、従来法の
ｌｏｔ ｏｎ処理した時点での酸洗液の脱スケール力に
匹敵し、また、本発明法による酸回収中濃度酸洗液は従
来法に比べて酸濃度がかなり低いにもかかわらず、従来
法の２００ｔ ｏｎ処理した時点での酸洗液の脱スケー
ル力を上回る脱スケール力を有し、本発明法による低濃
度酸洗液の脱スケール力は従来法に比べて酸濃度がかな
り低いにもかかわらず、従来法の２００ｔｏｎ処理した
時点での酸洗液の脱スケールカにほぼ匹敵していること
が明らかである．
すなわち、本発明法によれば、鉄イオン濃度比（ Ｆ
ｅ ２” ／ Ｆ ｅ ’ ” ）が０．２５ 〜２．
０（７）ｉ囲内でバランスよく維持されているので、酸
濃度を高いレベルにすることなく大きな脱スケールカが
得られることが明らかであり、酸濃度の低下によって酸
とくに硝酸の蒸発損失を少なくすることが可能であり、
硝酸の原単位を従来法に比べて３分の１程度に少なくで
きた．(Means for Solving the Problems) The metal pickling treatment method according to the present invention leads the pickling liquid in the pickling tank to the outside of the pickling tank, recovers nitric acid and hydrofluoric acid using an ion exchange membrane, and recovers the pickling solution. In a metal pickling treatment method in which the concentration of fluoronitric acid in the pickling solution is kept constant by replenishing the acid with new acid as necessary, the total iron concentration in the pickling solution is adjusted to 50 g/!
L or less and divalent iron ion (pe 2 + )
and trivalent iron ion (pe W + ) concentration ratio (F
e2+/p'e3+) is controlled within a range of 0.25 to 2.0, and in one embodiment, the nitric acid concentration of the pickling bath is controlled to be 0.35 to 0.6.
0N, and the hydrofluoric acid concentration is controlled within the range of 0.30 to 0.50N. In the metal pickling treatment method according to the present invention, the pickling liquid constituting the pickling bath in the pickling tank is led out of the pickling tank, nitric acid and hydrofluoric acid are recovered by an ion exchange membrane, and the recovered acid is The target is a constant concentration pickling process in which the concentration of fluoronitric acid in the pickling solution is kept constant by replenishing new acid as necessary. Figure 1 shows an embodiment of this constant concentration pickling process. It is. That is, as shown in Fig. 1, there is a pickling tank 2 containing a fluoronitric acid solution 1, which is a mixture of hydrofluoric acid and nitric acid, as a pickling solution, and an acid recovery device using a diffusion dialysis method using an ion exchange membrane. 3 is connected by a pipe 4, and a pipe 5 connected to the recovered liquid outlet of the acid recovery device 3 is arranged on the upper side of the pickling tank 2. Therefore, for example, during the pickling treatment of stainless steel, the fluoronitric acid solution 1 whose concentration has been reduced by the pickling treatment is sent as a stock solution into the acid recovery device 3 through the pipe 4, and water is also sent through the pipe 6. This acid recovery device! l
3, acid recovery processing is performed by diffusion dialysis using an ion-exchange membrane while the stock solution and water are supplied, and a recovery solution in which hydrofluoric acid and nitric acid are recovered and a waste fluoronitric acid solution are sent out. is sent into the pickling tank 2 through piping 5, and the waste fluoronitric acid solution is discharged through pipe 7, and this waste fluoronitric acid solution is neutralized and disposed of or used for other purposes. In 1, the necessary new acid is supplied from pipe 8,
Constant concentration pickling treatment is performed. In the metal pickling method according to the present invention, as described above, in a constant concentration operation in which the fluoronitric acid concentration of the pickling solution is controlled at a constant level, the total iron concentration in the pickling solution is kept at 50.
g/! L or less and the concentration ratio of divalent iron ions (Fe'') and trivalent iron ions (Fe'') ( }' e 2
+/Fe 3 + ) is controlled within the range of 0.25 to 2.0, and the reason for this limitation will be described below. Figure 2 shows that divalent iron ions (Fe 2 +)
and trivalent iron 7 (Fe' ”) (1) D degree ratio (F
e2''/Fe' +) and the descaling force.
) and trivalent iron ions (Fe”) have a large effect on the descaling force. In other words, on the vertical axis in Figure 2, the descaling force 3 is the amount of acid that is completely descaled. Descaling power 2 indicates that it has a pickling power that causes scale residue in a dotted shape, and descaling power 1 indicates that it has a pickling power that causes scale residue in a line or planar shape. In the pickling solution using fluoronitric acid, the iron ion concentration ratio (
Fe"/Fe") is 1.0*-t' is a trivalent iron ion (
It is clear that the descaling force is stronger because there are more Fe' ions (
As Fe2+) increases, the iron ion concentration ratio (F
When e2◆/F e8◆) exceeds 1.0, a decrease in descaling power is observed. As described above, as the amount of divalent iron ions (Fe 2 + ) increases, the descaling ability decreases, but in actual operation, the iron ion concentration ratio (p' 6 2 +/
Even if FeA+) is around 2.0, it has sufficient descaling power, so the iron ion concentration ratio (FeA+) in the pickling bath
2 + /F e3 + ) was set to 2.0 or less. In addition, the pickling solution in the pickling tank is led out of the pickling tank, nitric acid and hydrofluoric acid are recovered using an ion exchange membrane, and the recovered acid is replenished with new acid as needed to increase the concentration of fluorinated nitric acid in the pickling bath. When carrying out constant concentration operation where the pickling liquid is controlled at a constant level, it is actually difficult to control the iron ion concentration ratio (Fe''/Fe3+) of the pickling solution to less than 0.25 from the perspective of maintaining operation. Therefore, the lower limit of the iron ion concentration ratio (Fe”/Fe”) is 0.25
It was. In this way, when performing pickling treatment using a fluoronitric acid solution, hydrofluoric acid (HF) and nitric acid (H
It is recognized that it is not necessary to raise the concentration level of NO3) to a high concentration level, but rather that it is important to set the iron ion concentration ratio (Fe''/Fe W + ) within an appropriate range, and the pickling treatment method according to the present invention The iron ion concentration ratio (Fe
2 + /Fe+s◆) is to be controlled within the range of 0.25 to 2.0 (7). On the other hand, if the iron concentration in the pickling solution is too high, the pickling power will also decrease, so it was decided to control the total iron concentration in the pickling solution to 50 g/fL or less. Figure 3 shows the influence of pickling bath temperature and nitric acid concentration on nitric acid evaporation, and most of the conventional use (circled with diagonal lines) is in the nitric acid evaporation region. Therefore, if you try to keep the nitric acid concentration and pickling bath temperature constant in the fluoronitric acid solution, the amount of nitric acid that evaporates is large, so you have to replenish it one after another, and the amount of nitric acid used is quite large. It becomes something. On the other hand, as mentioned above, it has become clear that it is not necessary to use high concentrations of nitric acid and hydrofluoric acid if the iron ion concentration ratio (p e 2+ / Fe A + ) is controlled within an appropriate range during descaling. Therefore, the concentration of nitric acid in the pickling solution was 0.35 to 0, which is below the evaporation start line.
．． It is desirable to control the pressure to a low level of around 60N. Also,
The above-mentioned nitric acid ( HNO3) together with hydrofluoric acid (HNO3)
It is desirable to set the concentration of F), and it is also desirable to control the concentration of hydrofluoric acid to a low level of about 0.30 to 0.50N. Considering the descaling mechanism by pickling treatment using such a fluoronitric acid solution, as shown in Figure fJIJ4, it is hydrofluoric acid (HF) and trivalent iron ions (p' e 3 + ) and nitric acid (HNO
a) is a so-called catalyst that attacks trivalent iron ions (Fe'') and converts it into divalent iron ions (Fe2+), which then returns to trivalent iron ions (pe3+), which have descaling power. Therefore, as mentioned above, the divalent iron ion CF,2
+) and trivalent iron ions (in FeA), sufficient descaling performance can be obtained even if the concentration of nitric acid (HNO3) is kept to a low level, and evaporation of nitric acid can be prevented. It turns out that it can be suppressed. (Operation of the invention) Since the metal pickling treatment method according to the present invention has the above-mentioned structure, a sufficiently strong pickling power can be obtained even when the concentration of the fluoronitric acid solution is low, and the acid concentration can be reduced. This has the effect of reducing the evaporation loss of acid. (Example) As test materials, SUS310 and SU with the composition shown in Table 1 were used.
S
After the ON treatment, a medium concentration pickling process is performed, and in the present invention, a constant concentration pickling process is performed by recovering three types of acids: high concentration, medium concentration, and low concentration, and the descaling time in these cases is investigated. Ta. The results are shown in Figure 5. As is clear from Table 2 and Figure 5, when the descaling power of the method of the present invention and the conventional method are compared, the descaling power of the acid recovery high concentration pickling solution by the method of the present invention is lower than that of the conventional method. Although the acid concentration is considerably lower than that of the conventional method, the descaling power of the pickling solution at the time of lot-on treatment is comparable to that of the conventional method. Although the acid concentration is considerably lower than that of the conventional method, it has a descaling power that exceeds the descaling power of the pickling solution at the time of 200 ton treatment, and the descaling power of the low concentration pickling solution by the method of the present invention is It is clear that the scaling force is almost comparable to the descaling force of the pickling solution at the time of 200 ton processing using the conventional method, even though the acid concentration is considerably lower than that of the conventional method. That is, according to the method of the present invention, the iron ion concentration ratio (F
e2"/Fe'") is 0.25 to 2.
0(7)i, it is clear that a large descaling force can be obtained without increasing the acid concentration to a high level, and the reduction in acid concentration reduces the evaporation loss of acids, especially nitric acid. It is possible to
The basic unit of nitric acid was reduced to about one-third compared to the conventional method.
この発明に係わる金属の酸洗処理方法では、酸洗液を酸
洗槽外に導いてイオン交換膜により硝酸および弗酸を回
収し、酸洗液の弗硝酸濃度を一定に管理して定濃度酸洗
処理を行う方法において、酸洗液中のトータル鉄濃度を
５ ０ ｇｌ文以下とし且つ２価の鉄イオン（ ｝’
ｅ ２ ＋ ）と３価の鉄イオン（Ｆｅ３＋）の濃度比
（ ｐ ｅ ２ ＋ ／ ｐ ｅ ３ ＋ ）を０．２
５〜２．０の範囲に制御するようにしたから、酸洗処理
される金属の種類に対応した濃度の酸洗液を用いてそれ
ぞれの金属に対する定濃度酸洗処理を連続して行うこと
が可能であって従来のよラに酸洗液の濃度低下に対応し
て金属を選択するという制約がなくなり、このような酸
洗処理を行うに際して酸洗液の濃度を高めることなく、
低レベルの濃度において良好なる酸洗処理を行うことが
可能であり、必要に応じて高濃度，中濃度，低濃度にお
ける酸洗処理を任意の時期において効率よく行うことが
できるようになり、さらには酸洗液濃度の低下による酸
とくに硝酸の蒸発損失を防止して酸コストの大幅な低減
をもたらすことが可能であるという著しく優れた効果が
得られる．In the method for pickling metals according to the present invention, the pickling solution is led out of the pickling tank, nitric acid and hydrofluoric acid are recovered by an ion exchange membrane, and the concentration of fluoronitric acid in the pickling solution is controlled to be constant. In the pickling treatment method, the total iron concentration in the pickling solution is 50 gl or less, and divalent iron ions ( }'
e 2 + ) and trivalent iron ion (Fe3+) concentration ratio ( p e 2 + / p e 3 + ) to 0.2.
Since it is controlled within the range of 5 to 2.0, it is possible to continuously perform fixed concentration pickling treatment for each metal using a pickling solution with a concentration corresponding to the type of metal to be pickled. It is possible to eliminate the constraint of selecting a metal in response to a decrease in the concentration of the pickling solution as in the past, and to perform such pickling treatment without increasing the concentration of the pickling solution.
It is now possible to perform good pickling treatment at low concentrations, and it is now possible to efficiently perform pickling treatment at high, medium, and low concentrations at any time as needed. This method has the remarkable effect of preventing the evaporation loss of acid, especially nitric acid, due to a decrease in the concentration of the pickling solution, resulting in a significant reduction in acid cost.
第１図はこの発明に係わる金属の酸洗処理方法において
用いられる酸洗液の定濃度操業の実施態様を示す説明図
、第２図は鉄イオン濃度（Ｆｅ”／Ｆｅ”）と脱スケー
ルカとの関係を例示するグラフ、第３図は酸洗浴温度と
硝酸濃度と硝酸の蒸発開始ラインとの関係を例示するグ
ラフ、第４図は弗硝酸液を用いた酸洗処理による脱スケ
ール機構を示す説明図、第５図は実施例の結果を脱スケ
ール時間によって示す説明図である．
１・・・弗硝酸液（酸洗液）、
２・・・酸洗槽、
３・・・イオン交換膜による酸回収装置．ＨＮＯ３濠＆
（Ｎ）
５
ｅ−ｑド潅Fig. 1 is an explanatory diagram showing an embodiment of constant concentration operation of the pickling solution used in the metal pickling treatment method according to the present invention, and Fig. 2 shows the iron ion concentration (Fe''/Fe'') and the descaling force. Figure 3 is a graph illustrating the relationship between pickling bath temperature, nitric acid concentration, and nitric acid evaporation start line. Figure 4 shows the descaling mechanism by pickling treatment using a fluoronitric acid solution. Explanatory diagram, FIG. 5 is an explanatory diagram showing the results of the example in terms of descaling time. 1... Fluoronitric acid solution (pickling solution), 2... Pickling tank, 3... Acid recovery device using an ion exchange membrane. HNO3 moat &
(N) 5 e-q doh
Claims (2)
膜により硝酸および弗酸を回収し、回収した酸に必要に
応じて新酸を補充して酸洗液の弗硝酸濃度を一定に管理
する金属の酸洗処理方法において、酸洗液中のトータル
鉄濃度を５０ｇ／ｌ以下とし且つ２価の鉄イオン（Ｆｅ
＾２＾＋）と３価の鉄イオン（Ｆｅ＾５＾＋）の濃度比
（Ｆｅ＾２＾＋／Ｆｅ＾３＾＋）を０．２５〜２．０の
範囲に制御することを特徴とする金属の酸洗処理方法。(1) The pickling solution in the pickling tank is guided outside the pickling tank, nitric acid and hydrofluoric acid are recovered using an ion exchange membrane, and the recovered acid is replenished with new acid as needed to make the pickling solution In a metal pickling treatment method in which the nitric acid concentration is controlled at a constant level, the total iron concentration in the pickling solution is set to 50 g/l or less, and divalent iron ions (Fe
The feature is that the concentration ratio (Fe^2^+/Fe^3^+) of trivalent iron ions (Fe^2^+) and trivalent iron ions (Fe^5^+) is controlled within the range of 0.25 to 2.0. A pickling treatment method for metals.
濃度を０．３０〜０．５０Ｎの範囲に制御することを特
徴とする請求項第（１）項に記載の金属の酸洗処理方法
。(2) The metal according to claim (1), characterized in that the nitric acid concentration of the pickling solution is controlled within the range of 0.35 to 0.60N, and the hydrofluoric acid concentration is controlled within the range of 0.30 to 0.50N. pickling treatment method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1161732A JP2827289B2 (en) | 1989-06-23 | 1989-06-23 | Pickling treatment method for metals |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1161732A JP2827289B2 (en) | 1989-06-23 | 1989-06-23 | Pickling treatment method for metals |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0328386A true JPH0328386A (en) | 1991-02-06 |
| JP2827289B2 JP2827289B2 (en) | 1998-11-25 |
Family
ID=15740832
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1161732A Expired - Lifetime JP2827289B2 (en) | 1989-06-23 | 1989-06-23 | Pickling treatment method for metals |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2827289B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1460148A4 (en) * | 2001-12-25 | 2005-03-09 | Parker Corp | Method of surface-finishing stainless steel after descaling |
| WO2012098689A1 (en) | 2011-01-17 | 2012-07-26 | Ｊｆｅスチール株式会社 | Method for producing stainless steel for fuel cell separators, stainless steel for fuel cell separators, fuel cell separator, and fuel cell |
| EP3115482B1 (en) * | 2014-03-04 | 2022-01-26 | JFE Steel Corporation | Cold-rolled steel sheet, manufacturing method therefor, and car part |
| KR20230137338A (en) | 2021-01-27 | 2023-10-04 | 닛뽄 가야쿠 가부시키가이샤 | Catalyst and method for producing unsaturated carboxylic acid using the same |
| KR20230137913A (en) | 2021-01-27 | 2023-10-05 | 닛뽄 가야쿠 가부시키가이샤 | Catalyst and method for producing unsaturated carboxylic acid using the same |
-
1989
- 1989-06-23 JP JP1161732A patent/JP2827289B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1460148A4 (en) * | 2001-12-25 | 2005-03-09 | Parker Corp | Method of surface-finishing stainless steel after descaling |
| WO2012098689A1 (en) | 2011-01-17 | 2012-07-26 | Ｊｆｅスチール株式会社 | Method for producing stainless steel for fuel cell separators, stainless steel for fuel cell separators, fuel cell separator, and fuel cell |
| KR20170026648A (en) | 2011-01-17 | 2017-03-08 | 제이에프이 스틸 가부시키가이샤 | Method for producing stainless steel for fuel cell separators, stainless steel for fuel cell separators, fuel cell separator, and fuel cell |
| US9653738B2 (en) | 2011-01-17 | 2017-05-16 | Jfe Steel Corporation | Method for producing stainless steel for fuel cell separator, stainless steel for fuel cell separator, fuel cell separator, and fuel cell |
| EP3115482B1 (en) * | 2014-03-04 | 2022-01-26 | JFE Steel Corporation | Cold-rolled steel sheet, manufacturing method therefor, and car part |
| KR20230137338A (en) | 2021-01-27 | 2023-10-04 | 닛뽄 가야쿠 가부시키가이샤 | Catalyst and method for producing unsaturated carboxylic acid using the same |
| KR20230137913A (en) | 2021-01-27 | 2023-10-05 | 닛뽄 가야쿠 가부시키가이샤 | Catalyst and method for producing unsaturated carboxylic acid using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2827289B2 (en) | 1998-11-25 |
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